X-Git-Url: https://git.sesse.net/?p=remoteglot;a=blobdiff_plain;f=Board.pm;h=3e0fd33a52b4fa72a4264a4eff58962dc93cc197;hp=3d832781bc2b1d4dc84b89daa3b933b2d57dcdd0;hb=960b6ea34239ae508e3ab9841665fd7ba390fba3;hpb=71b759f677572c77367ec2ba12c5c67fc0e941b7

diff --git a/Board.pm b/Board.pm
index 3d83278..3e0fd33 100644
--- a/Board.pm
+++ b/Board.pm
@@ -148,6 +148,8 @@ sub move_to_uci_notation {
 	return _pos_to_square($from_row, $from_col) . _pos_to_square($to_row, $to_col) . $promo;
 }
 
+# Note: This is in general not a validation that the move is actually allowed
+# (e.g. you can castle even though you're in check).
 sub parse_pretty_move {
 	my ($board, $move, $toplay) = @_;
 
@@ -170,40 +172,48 @@ sub parse_pretty_move {
 
 	# Parse promo
 	my $promo;
-	if ($move =~ s/=([QRNB])$//) {
+	if ($move =~ s/=?([QRNB])$//) {
 		$promo = $1;
 	}
 
 	$move =~ /^([KQRBN])?([a-h])?([1-8])?x?([a-h][1-8])$/ or die "Invalid move $move";
-	my $piece = $1 // 'P';
+	my $piece = $1;
 	my $from_col = defined($2) ? _col_letter_to_num($2) : undef;
 	my $from_row = defined($3) ? _row_letter_to_num($3) : undef;
+	if (!defined($piece) && (!defined($from_col) || !defined($from_row))) {
+		$piece = 'P';
+	}
 	my ($to_row, $to_col) = _square_to_pos($4);
 	
 	# Find all possible from-squares that could have been meant.
 	my @squares = ();
+	my $side = 'K';
 	if ($toplay eq 'B') {
-		$piece = lc($piece);
+		$piece = lc($piece) if defined($piece);
+		$side = 'k';
 	}
 	for my $row (0..7) {
 		next if (defined($from_row) && $from_row != $row);
 		for my $col (0..7) {
 			next if (defined($from_col) && $from_col != $col);
-			next if ($board->[$row][$col] ne $piece);
-			next if (!$board->can_reach($piece, $row, $col, $to_row, $to_col));
-
-			# See if doing this move would put us in check
-			# (yes, there are clients that expect us to do this).
-			my $check = $board->make_move($row, $col, $to_row, $to_col, $promo)->in_check();
-			next if ($check eq 'both' ||
-			         ($toplay eq 'W' && $check eq 'white') ||
-			         ($toplay eq 'B' && $check eq 'black'));
-
+			next if (defined($piece) && $board->[$row][$col] ne $piece);
 			push @squares, [ $row, $col ];
 		}
 	}
+	if (scalar @squares > 1) {
+		# Filter out pieces which cannot reach this square.
+		@squares = grep { $board->can_reach($piece, $_->[0], $_->[1], $to_row, $to_col) } @squares;
+	}
+	if (scalar @squares > 1) {
+		# See if doing this move would put us in check
+		# (yes, there are clients that expect us to do this).
+		@squares = grep { !$board->make_move($_->[0], $_->[1], $to_row, $to_col, $promo)->in_check($side) } @squares;
+	}
+	if (scalar @squares == 0) {
+		die "Impossible move $move";
+	}
 	if (scalar @squares != 1) {
-		die "Ambigious or impossible move $move";
+		die "Ambigious move $move";
 	}
 	return (@{$squares[0]}, $to_row, $to_col, $promo);
 }
@@ -220,6 +230,45 @@ sub fen {
 	return join('/', @rows);
 }
 
+# Returns a compact bit string describing the same data as fen().
+# This is encoded using a Huffman-like encoding, and should be
+# typically about 1/3 the number of bytes.
+sub bitpacked_fen {
+	my ($board) = @_;
+	my $bits = "";
+
+	for my $row (0..7) {
+		for my $col (0..7) {
+			my $piece = $board->[$row][$col];
+			if ($piece eq '-') {
+				$bits .= "0";
+				next;
+			}
+
+			my $color = (lc($piece) eq $piece) ? 0 : 1;
+			$bits .= "1" . $color;
+
+			if (lc($piece) eq 'p') {
+				$bits .= "0";
+			} elsif (lc($piece) eq 'n') {
+				$bits .= "100";
+			} elsif (lc($piece) eq 'b') {
+				$bits .= "101";
+			} elsif (lc($piece) eq 'r') {
+				$bits .= "1110";
+			} elsif (lc($piece) eq 'q') {
+				$bits .= "11110";
+			} elsif (lc($piece) eq 'k') {
+				$bits .= "11111";
+			} else {
+				die "Unknown piece $piece";
+			}
+		}
+	}
+
+	return pack('b*', $bits);
+}
+
 sub can_reach {
 	my ($board, $piece, $from_row, $from_col, $to_row, $to_col) = @_;
 	
@@ -228,10 +277,46 @@ sub can_reach {
 	if ($dest_piece ne '-') {
 		return 0 if (($piece eq lc($piece)) == ($dest_piece eq lc($dest_piece)));
 	}
-
-	if (lc($piece) eq 'k') {
-		return (abs($from_row - $to_row) <= 1 && abs($from_col - $to_col) <= 1);
+	
+	if ($piece eq 'p') {
+		# black pawn
+		if ($to_col == $from_col && $to_row == $from_row + 1) {
+			return ($dest_piece eq '-');
+		}
+		if ($to_col == $from_col && $from_row == 1 && $to_row == 3) {
+			my $middle_piece = $board->[2][$to_col];
+			return ($dest_piece eq '-' && $middle_piece eq '-');
+		}
+		if (abs($to_col - $from_col) == 1 && $to_row == $from_row + 1) {
+			if ($dest_piece eq '-') {
+				# En passant. TODO: check that the last move was indeed an EP move
+				return ($to_row == 5 && $board->[4][$to_col] eq 'P');
+			} else {
+				return 1;
+			}
+		}
+		return 0;
 	}
+	if ($piece eq 'P') {
+		# white pawn
+		if ($to_col == $from_col && $to_row == $from_row - 1) {
+			return ($dest_piece eq '-');
+		}
+		if ($to_col == $from_col && $from_row == 6 && $to_row == 4) {
+			my $middle_piece = $board->[5][$to_col];
+			return ($dest_piece eq '-' && $middle_piece eq '-');
+		}
+		if (abs($to_col - $from_col) == 1 && $to_row == $from_row - 1) {
+			if ($dest_piece eq '-') {
+				# En passant. TODO: check that the last move was indeed an EP move
+				return ($to_row == 2 && $board->[3][$to_col] eq 'p');
+			} else {
+				return 1;
+			}
+		}
+		return 0;
+	}
+	
 	if (lc($piece) eq 'r') {
 		return 0 unless ($from_row == $to_row || $from_col == $to_col);
 
@@ -294,108 +379,70 @@ sub can_reach {
 		return (can_reach($board, 'R', $from_row, $from_col, $to_row, $to_col) ||
 		        can_reach($board, 'B', $from_row, $from_col, $to_row, $to_col));
 	}
-
-	if ($piece eq 'p') {
-		# black pawn
-		if ($to_col == $from_col && $to_row == $from_row + 1) {
-			return ($dest_piece eq '-');
-		}
-		if ($to_col == $from_col && $from_row == 1 && $to_row == 3) {
-			my $middle_piece = $board->[2][$to_col];
-			return ($dest_piece eq '-' && $middle_piece eq '-');
-		}
-		if (abs($to_col - $from_col) == 1 && $to_row == $from_row + 1) {
-			if ($dest_piece eq '-') {
-				# En passant. TODO: check that the last move was indeed an EP move
-				return ($to_row == 5 && $board->[4][$to_col] eq 'P');
-			} else {
-				return 1;
-			}
-		}
-		return 0;
-	}
-	if ($piece eq 'P') {
-		# white pawn
-		if ($to_col == $from_col && $to_row == $from_row - 1) {
-			return ($dest_piece eq '-');
-		}
-		if ($to_col == $from_col && $from_row == 6 && $to_row == 4) {
-			my $middle_piece = $board->[5][$to_col];
-			return ($dest_piece eq '-' && $middle_piece eq '-');
-		}
-		if (abs($to_col - $from_col) == 1 && $to_row == $from_row - 1) {
-			if ($dest_piece eq '-') {
-				# En passant. TODO: check that the last move was indeed an EP move
-				return ($to_row == 2 && $board->[3][$to_col] eq 'p');
-			} else {
-				return 1;
-			}
-		}
-		return 0;
+	if (lc($piece) eq 'k') {
+		return (abs($from_row - $to_row) <= 1 && abs($from_col - $to_col) <= 1);
 	}
-	
+
 	# unknown piece
 	return 0;
 }
 
-# Returns 'none', 'white', 'black' or 'both', depending on which sides are in check.
-# The latter naturally indicates an invalid position.
-sub in_check {
-	my $board = shift;
-	my ($black_check, $white_check) = (0, 0);
+# Like can_reach, but also checks the move doesn't put the side in check.
+# We use this in prettyprint_move to reduce the disambiguation, because Chess.js
+# needs moves to be in minimally disambiguated form.
+sub can_legally_reach {
+	my ($board, $piece, $from_row, $from_col, $to_row, $to_col) = @_;
+
+	return 0 if (!can_reach($board, $piece, $from_row, $from_col, $to_row, $to_col));
 
-	my ($wkr, $wkc, $bkr, $bkc) = _find_kings($board);
+	my $nb = $board->make_move($from_row, $from_col, $to_row, $to_col);
+	my $side = ($piece eq lc($piece)) ? 'k' : 'K';
 
-	# check all pieces for the possibility of threatening the two kings
+	return !in_check($nb, $side);
+}
+
+my %pieces_against_side = (
+	k => { K => 1, Q => 1, R => 1, N => 1, B => 1, P => 1 },
+	K => { k => 1, q => 1, r => 1, n => 1, b => 1, p => 1 },
+);
+
+# Returns whether the given side (given as k or K for black and white) is in check.
+sub in_check {
+	my ($board, $side) = @_;
+	my ($kr, $kc) = _find_piece($board, $side);
+
+	# check all pieces for the possibility of threatening this king
 	for my $row (0..7) {
+		next unless grep { exists($pieces_against_side{$side}{$_}) } @{$board->[$row]};
 		for my $col (0..7) {
 			my $piece = $board->[$row][$col];
 			next if ($piece eq '-');
-		
-			if (uc($piece) eq $piece) {
-				# white piece
-				$black_check = 1 if ($board->can_reach($piece, $row, $col, $bkr, $bkc));
-			} else {
-				# black piece
-				$white_check = 1 if ($board->can_reach($piece, $row, $col, $wkr, $wkc));
-			}
+			return 1 if ($board->can_reach($piece, $row, $col, $kr, $kc));
 		}
 	}
 
-	if ($black_check && $white_check) {
-		return 'both';
-	} elsif ($black_check) {
-		return 'black';
-	} elsif ($white_check) {
-		return 'white';
-	} else {
-		return 'none';
-	}
+	return 0;
 }
 
-sub _find_kings {
-	my $board = shift;
-	my ($wkr, $wkc, $bkr, $bkc);
+sub _find_piece {
+	my ($board, $piece) = @_;
 
 	for my $row (0..7) {
+		next unless grep { $_ eq $piece } @{$board->[$row]};
 		for my $col (0..7) {
-			my $piece = $board->[$row][$col];
-			if ($piece eq 'K') {
-				($wkr, $wkc) = ($row, $col);
-			} elsif ($piece eq 'k') {
-				($bkr, $bkc) = ($row, $col);
+			if ($board->[$row][$col] eq $piece) {
+				return ($row, $col);
 			}
 		}
 	}
 
-	return ($wkr, $wkc, $bkr, $bkc);
+	return (undef, undef);
 }
 
-# Returns if any side is in mate.
+# Returns if the given side (given as k or K) is in mate.
 sub in_mate {
-	my $board = shift;
-	my $check = $board->in_check();
-	return 0 if ($check eq 'none');
+	my ($board, $side, $in_check) = @_;
+	return 0 if (!$in_check);
 
 	# try all possible moves for the side in check
 	for my $row (0..7) {
@@ -403,7 +450,7 @@ sub in_mate {
 			my $piece = $board->[$row][$col];
 			next if ($piece eq '-');
 
-			if ($check eq 'white') {
+			if ($side eq 'K') {
 				next if ($piece eq lc($piece));
 			} else {
 				next if ($piece eq uc($piece));
@@ -414,11 +461,8 @@ sub in_mate {
 					next if ($row == $dest_row && $col == $dest_col);
 					next unless ($board->can_reach($piece, $row, $col, $dest_row, $dest_col));
 
-					my $nb = $board->clone();
-					$nb->[$row][$col] = '-';
-					$nb->[$dest_row][$dest_col] = $piece;
-					my $new_check = $nb->in_check();
-					return 0 if ($new_check ne $check && $new_check ne 'both');
+					my $nb = $board->make_move($row, $col, $dest_row, $dest_col);
+					return 0 if (!$nb->in_check($side));
 				}
 			}
 		}
@@ -434,14 +478,31 @@ sub prettyprint_move {
 	my $pretty = $board->_prettyprint_move_no_check_or_mate($from_row, $from_col, $to_row, $to_col, $promo);
 
 	my $nb = $board->make_move($from_row, $from_col, $to_row, $to_col, $promo);
-	if ($nb->in_mate()) {
+
+	my $piece = $board->[$from_row][$from_col];
+	my $other_side = (uc($piece) eq $piece) ? 'k' : 'K';
+	my $in_check = $nb->in_check($other_side);
+	if ($nb->in_mate($other_side, $in_check)) {
 		$pretty .= '#';
-	} elsif ($nb->in_check() ne 'none') {
+	} elsif ($in_check) {
 		$pretty .= '+';
 	}
 	return ($pretty, $nb);
 }
 
+sub num_pieces {
+	my ($board) = @_;
+
+	my $num = 0;
+	for my $row (0..7) {
+		for my $col (0..7) {
+			my $piece = $board->[$row][$col];
+			++$num if ($piece ne '-');
+		}
+	}
+	return $num;	
+}
+
 sub _prettyprint_move_no_check_or_mate {
         my ($board, $from_row, $from_col, $to_row, $to_col, $promo) = @_;
 	my $piece = $board->[$from_row][$from_col];
@@ -453,22 +514,22 @@ sub _prettyprint_move_no_check_or_mate {
 
 	# white short castling
 	if ($move eq 'e1g1' && $piece eq 'K') {
-		return '0-0';
+		return 'O-O';
 	}
 
 	# white long castling
 	if ($move eq 'e1c1' && $piece eq 'K') {
-		return '0-0-0';
+		return 'O-O-O';
 	}
 
 	# black short castling
 	if ($move eq 'e8g8' && $piece eq 'k') {
-		return '0-0';
+		return 'O-O';
 	}
 
 	# black long castling
 	if ($move eq 'e8c8' && $piece eq 'k') {
-		return '0-0-0';
+		return 'O-O-O';
 	}
 
 	my $pretty;
@@ -480,12 +541,12 @@ sub _prettyprint_move_no_check_or_mate {
 			$pretty = substr($move, 0, 1) . 'x' . _pos_to_square($to_row, $to_col);
 		} else {
 			$pretty = _pos_to_square($to_row, $to_col);
+		}
 
-			if (defined($promo) && $promo ne '') {
-				# promotion
-				$pretty .= "=";
-				$pretty .= $promo;
-			}
+		if (defined($promo) && $promo ne '') {
+			# promotion
+			$pretty .= "=";
+			$pretty .= uc($promo);
 		}
 		return $pretty;
 	}
@@ -497,7 +558,7 @@ sub _prettyprint_move_no_check_or_mate {
 	for my $col (0..7) {
 		for my $row (0..7) {
 			next unless ($board->[$row][$col] eq $piece);
-			++$num_total if ($board->can_reach($piece, $row, $col, $to_row, $to_col));
+			++$num_total if ($board->can_legally_reach($piece, $row, $col, $to_row, $to_col));
 		}
 	}
 
@@ -505,14 +566,14 @@ sub _prettyprint_move_no_check_or_mate {
 	my $num_row = 0;
 	for my $col (0..7) {
 		next unless ($board->[$from_row][$col] eq $piece);
-		++$num_row if ($board->can_reach($piece, $from_row, $col, $to_row, $to_col));
+		++$num_row if ($board->can_legally_reach($piece, $from_row, $col, $to_row, $to_col));
 	}
 
 	# and same for columns
 	my $num_col = 0;
 	for my $row (0..7) {
 		next unless ($board->[$row][$from_col] eq $piece);
-		++$num_col if ($board->can_reach($piece, $row, $from_col, $to_row, $to_col));
+		++$num_col if ($board->can_legally_reach($piece, $row, $from_col, $to_row, $to_col));
 	}
 
 	# see if we need to disambiguate